Hot water pressure washers have numerous applications in the industry, such as in cleaning the inside of ovens and furnaces. Hot water applied at a high pressure on a surface is known to have superior cleaning advantages. Hot water pressure washers first use a water pump to generate a continuous flow of high pressure cold water. The high pressure cold water is then passed through a heat exchanger, usually a coil type heat exchanger, to generate a continuous flow of high pressure hot water. The hot water is then taken to a hand held trigger gun and nozzle of a wand to guide the water on a surface for cleaning.
The prior art uses flame combustion to produce the heat required to heat water for use in hot pressure washing equipment. This technology has limitations due to low heat transfer efficiency and high carbon monoxide emissions. These devices also generate corrosive condensates. The use of natural gas, propane or butane gases in these systems produce corrosive condensates when the flue gasses cool past their dew point—the water vapor produced by combustion condensates in the presence of carbon dioxide produces carbonic acids. These acids can corrode metals and cause premature appliance and component failure.
The prior art devices that use flame ball to heat the water have an open bottom burner. The combustion gases rise up the outer area of the flame envelope causing a cooling effect on the lower part of the water heating coil. This restricts the amount of heat that is transferred to the lower part of the coil, which is the coolest due to the incoming water entering the lower end of the coil. The only way to get the heat to transfer to this area of the coil is by scrubbing the flue gasses to the side of the water heating coil. This scrubbing is greatly reduced by the up flow of cool rising air from below the coil entering the flame envelope.
The burners in the prior art devices comprises of numerous individual burner nozzles injecting fuel inside a combustion chamber. The air needed to burn the fuel enters from the surrounding through open bottom design of these burners. The fuel nozzles are generally aimed at the water coils for scrubbing purposes to produce heat transfer to the coil. The turbulence caused by burners passing over and through each other tends to create excessive amounts of carbon monoxide, CO. Many Countries have limitations on the amount of CO produced by gas burning appliances. The current fix is to de-rate the burner and fire it at a less BTU heat output to lower emissions; unfortunately this also reduces the heat output.
The present invention introduces application of an infrared burner to heat the water in hot water washers. This device greatly increases heat transfer of these burners, especially, at the lower parts of the heat exchanger, close to the cold water inlet. The additional heat transfer virtually eliminates the problematic condensation of flue gasses on the lower part of the coil which produce corrosive carbonic acids that destroy steel and cast iron.